Monolithic integration of hemt devices of normally-off type with hemt devices of normally-on type

A method for manufacturing a semiconductor die including an E-mode HEMT or E-mode MIS-HEMT device at a first region of the semiconductor die and a D-mode MIS-HEMT device at a second region of the semiconductor die, the first region and the second region being at a distance from each other, wherein the method comprises:

• forming a heterostructure on a substrate of the semiconductor die, at both the first region and the second region;
• forming, on the heterostructure, a doped gate region of the E-mode HEMT or E-mode MIS-HEMT device, at the first region;
• forming a dielectric layer in the first region on the heterostructure and on the doped gate region and, concurrently, in the second region on the heterostructure, the dielectric layer being of a first material;
• forming a first insulating layer on the dielectric layer, at the first region and the second region, of a second material that may be selectively etched with respect to the first material;
• forming a first gate opening by etching the first insulating layer throughout an entire thickness and exposing the dielectric layer underlying, at the second region;
• forming a second gate opening by etching the first insulating layer throughout the entire thickness, at the doped gate region;
• and
• forming a gate conductive terminal of the D-mode MIS-HEMT device in the first gate opening and, concurrently, forming a respective gate conductive terminal of the E-mode HEMT or E-mode MIS-HEMT device in the second gate opening.